primate vs placental

primate and placental both are nouns.

Word	Noun	Adjective	Verb	Adverb
primate	Yes	No	No	No
placental	Yes	Yes	No	No

As nouns, placental is a hypernym of primate; that is, placental is a word with a broader meaning than primate:

primate: any placental mammal of the order Primates; has good eyesight and flexible hands and feet
placental: mammals having a placenta; all mammals except monotremes and marsupials

Other hypernyms of primate include eutherian, eutherian mammal, placental mammal.

primate (noun)	placental (noun)
any placental mammal of the order Primates; has good eyesight and flexible hands and feet	mammals having a placenta; all mammals except monotremes and marsupials
a senior clergyman and dignitary

primate (adjective)	placental (adjective)
	pertaining to or having or occurring by means of a placenta